Figure 2.
Neural correlates of NREM sleep oscillations as evidenced by fMRI
A. fMRI correlates of spindles. The upper panel shows a (stage 2) NREM sleep epoch depicting a typical spindle on scalp EEG recording. Brain activity is estimated for each detected spindle compared to the baseline brain activity of NREM sleep. The lower left panels shows the significant brain responses associated with spindles (P < 0.05, corrected for multiple comparisons on a volume of interest), including the thalamus, anterior cingulate cortex and insula (from top to bottom).42 Functional results are displayed on an individual structural image (display at P < 0.001, uncorrected), at different levels of the x, y, z axes as indicated for each section. The lower right panels show the time course (in seconds) of fitted response amplitudes (in arbitrary units) during spindles in the corresponding circled brain area. All responses consist in regional increases of brain activity.
B. fMRI correlates of slow waves. The upper panel shows a (stage 4) NREM sleep epoch depicting typical slow waves on scalp EEG recording. Brain activity is estimated for each detected slow wave compared to the baseline brain activity of NREM sleep. The lower panels shows the significant brain responses associated with slow waves (P < 0.05, corrected for multiple comparisons on a volume of interest), including the brainstem, cerebellum, parahippocampal gyrus, inferior frontal gyrus, precuneus and posterior cingulate gyrus (from left to right and top to bottom).40 Functional results are displayed on an individual structural image (display at P < 0.001, uncorrected), at different levels of the x, y, z axes as indicated for each section. The lower side panels show the time course (in seconds) of fitted response amplitudes (in arbitrary units) during slow wave in the corresponding circled brain area. All responses consist in regional increases of brain activity.
Copyright (2007, 2008) National Academy of Sciences, U.S.A.